Journal of Performance of Constructed Facilities

Vibration problems in stadia are becoming more common due to increased structural slenderness and more lively dynamic crowd excitation. Unfortunately, there is very little guidance available to design engineers dealing with the assessment and design of stadia structures. This paper presents unique data from a program of modal testing and in-service monitoring of a large contemporary cantilever grandstand in the United Kingdom. The in-service monitoring was carried out during an international football match, during which the stadium was full to capacity. Modal properties obtained from the testing on the empty structure are presented and the results from in-service monitoring are described. It is found that crowd occupation can significantly alter the modal properties of a stadium, and that the changes can vary according to the crowd configuration. Additionally, previously proposed methods for assessment of vibration serviceability have been applied and it has been shown that they can lead to inconsistent results, which is a result of their sensitivity to the data acquisition and analysis techniques used. It is concluded that it is very important that consistent methods of data acquisition, analysis, and vibration serviceability assessment are utilized by future researchers and practitioners. Also, further research is required to define vibration serviceability limits using the state-of-the-art vibration dose approach.

Building designers’ decisions affect long term quality and life cycle cost of buildings. Designers’ decisions are usually latent in nature and hard to detect at the early stage of construction. This research looks at failure mechanisms that caused design-related latent defects and the design parameters that could prevent these defects. A 9-month building survey on 74 buildings found that the three most important design-related failure causes were weather impact, impacts from occupants, and loads and moisture from the wet areas. Insufficient considerations for these failures causes were found to be the key in preventing these defects. The design strategies that could successfully prevent triggering these defects include aligning material performance against adverse weather conditions, preventing impacts from occupants and loads, preventing water leakage, improving specifications and improving design clarity, details, and layout. There are huge amount of standards and codes available internationally, however, each is designed specifically to overcome regional problems. This research confirms the need for designers to (1) consolidate regional standards and codes; (2) develop in-house database using existing standards and codes, and lesson-learned from defects gathered by property managers; and (3) to apply this knowledge to eliminate latent defects from future design. This research also confirms that such knowledge can be developed using existing records of property managers.

Several challenges and complexities are involved in managing affordable housing properties, including social programming, meeting financial goals, budgeting, complying with governmental and local housing regulations, decreasing tenant turnover and vacancy rates, and maintaining the physical building structure. Nonprofit organizations have recently taken on the task of housing the nation’s less privileged, lower-income households. Most nonprofit owners contract property management services to private management companies. This research measures how satisfied residents are with property management services at Defoors Ferry Manor, a nonprofit multifamily affordable housing community owned by Atlanta Mutual Housing Association. Of the thirteen variables, residents were least satisfied with expediency in which property management staff addressed their issues. A plausible explanation for this finding is the high turnover rate in property management staff. This research provides recommendations for successfully transitioning between property management staff.

Research in accelerated pavement testing (APT) facilities has traditionally focused on the pavement performance such as rutting and fatigue cracking, but documentation on construction management and information of the actual pavement construction quality is limited. There are typically four critical factors that need to be considered to achieve the best possible outcome in construction: cost, schedule, construction process, and quality control, and management. With the objective of developing guidelines for planning and executing construction of a small-scale APT facility, this paper presents a case study documenting and evaluating the construction process and construction management efforts of two sensor-instrumented hot mix asphalt pavement test sections built in a small-scale APT facility. The focus of the experiment was to study bottom-up fatigue cracking of the flexible pavement structure. The presented information and lessons learned serve as a template and guide for agencies pursuing this type of research and pavement construction.

Proper identification of the modes of vibration of a structure is crucial in order to avoid the condition of resonance under dynamic loading conditions. A combination of numerical simulation, physical experimentation, and waveform analysis was employed in order to obtain a dynamic evaluation of the reaction wall for the Network for Earthquake Engineering Simulation (NEES) large scale testing laboratory at Cornell University. The first four modes of vibration of the structure were identified, and this information is now available to researchers who design experiments that utilize the NEES facility. This paper presents the numerical (finite element) studies and a description of the impact test procedure used to excite and record the response of this massive, posttensioned, reinforced concrete structure. It also illustrates how numerical modeling aided in the design of experiments and how waveform analysis proved essential for the proper characterization of the dynamic behavior of this unusual structure.

Experimental field load-test and finite-element analysis were carried out for the performance assessment of a precast-concrete, modular, three-sided, low-profile, buried, arch bridge system. Finite-element analysis incorporated soil modeling and soil–structure interaction at service and limit load levels. The analytical study simulates step-by-step incremental phases of construction and service loads. The finite-element model was calibrated based on the experimental field assessment, to provide a better correlation between the analytically predicted behavior and the actual response of the structure. The study validates the incorporation of various soil models and soil–structure interaction characteristics, to allow a more cost-effective bridge design.

The paper presents an experimental study of the actual dynamic effects for a preselected typical highway bridge. Knowledge of the dynamic impact factors is important for accurate determination of the ultimate load capacity and performance assessment of constructed bridges. Static and dynamic field tests were performed on a two-lane concrete highway bridge built in 1999 on U.S. 90 in northwest Florida. During the tests, one or two fully loaded trucks crossed over the bridge, which was instrumented with strain gauges, accelerometers, and displacement transducers. A wooden plank was placed across the lanes for some runs to trigger extensive dynamic vibration and to simulate poor road surface conditions. Data collected from the tests were used for comprehensive assessment of the bridge under dynamic loading. Impact factors obtained from the tests with higher speeds were found larger than corresponding values recommended by bridge codes. Analysis revealed that stiff vehicle suspension, road surface imperfection, and “bouncing” of the truck loading contributed to the high impact factors. Experimental data were also used for validation of the finite-element models developed for the vehicle–bridge system.

Fuzzy logic is a means for modeling the uncertainty involved in describing an event/result using natural language. The fuzzy logic approach would be particularly useful for remedying the uncertainties and imprecision in bridge inspectors’ observations. This study explores the possibilities of using fuzzy mathematics for condition assessment and rating of bridges, developing a systematic procedure and formulations for rating existing bridges using fuzzy mathematics. Computer programs developed from formulations presented in this paper are used for evaluating the rating of existing bridges, and the details are presented in the paper. In this approach, the entire bridge has been divided into three major components—deck, superstructure, and substructure—each of which is further subdivided into a number of elements. Using fuzzy mathematics in combination with an eigenvector-based priority setting approach, the resultant rating set for the bridge has been evaluated based on the specified ratings and importance factors for all the elements of the bridge. Then the defuzzified value of the resultant rating fuzzy set becomes the rating value for the bridge as a whole. It is argued that the methodology presented in this paper would help the decision makers/bridge inspectors immensely.

Turkish bridge design standards were studied with a focus on the live load. Turkish design specifications were compared with American design specifications. Turkish bridge design specifications follow American Association of State Highway and Transportation Officials-Standard Specifications for Highway Bridges (AASHTO-SSHB), with the live load in Turkish standards given in tonnes, whereas in AASHTO-SSHB the live load is in tons. Turkish bridges are currently designed to either HS20 or HS30, the latter being 65% heavier than HS20-44. A reinforced concrete open spandrel arch bridge in Birecik, Turkey was analyzed using a service load approach according to AASHTO-SSHB with a heavy equipment transporter (HET), weighing $104,600\mathrm{kg}$ , as the live load. Dead load, live load, and impact were considered, and the analysis did not include any modification for possible deterioration, damage, or aging of the bridge. The bridge was not deemed adequate for passage of a HET using these assumptions.

An evaluation of commercial and experimental dust palliatives was conducted to determine their effectiveness for mitigating fugitive dust on roads in arid climates. Several types of chemicals were tested including polymer emulsions, lignosulfonates, chloride salts, synthetic fluids, an asphalt emulsion, a polysaccharide solution, a polyacrylamide, and a guar gum. Each product was placed in an individual test section at a rate of $3.8\mathrm{L}∕{\mathrm{m}}^2$ using an admix construction method (grade/spray/till/compact/spray). Fourteen test sections were constructed and observed at 30-day intervals to monitor product performance. Data from both stationary and mobile particle collectors were analyzed to determine the ability of each product to suppress dust for extended periods. Several products are recommended for use on roads in arid climates as a result of this evaluation.

This paper discusses the performance and analysis of four mechanically stabilized earth (MSE) wall bridge approaches shaken by the 2003 Tecomán, Mexico earthquake. Strong shaking during the earthquake caused varying degrees of permanent displacement in several of the MSE walls. Immediately after the earthquake a geotechnical engineering reconnaissance team made detailed damage surveys of each wall. Complete design and construction data were later obtained. The analyses indicate that pullout of the upper reinforcement layers was the mechanism most likely responsible for the seismically induced deformation of the MSE walls. The upper layers of reinforcement were vulnerable to pullout because of the low levels of confining stress and the limited number of reinforcing elements per unit width. While pullout was the principal deformation mechanism, other factors contributing to deformation include large peak ground acceleration, more than twice the design value, and possible directional effects in the ground motion, which directed significant energy to the direction perpendicular to some of the walls. The latter finding concurs with observations made during the reconnaissance, where a clear directional bias was observed in the MSE wall deformations. The applicability and validity of the pseudostatic and sliding block methods of seismic analyses are discussed in light of the observed performance.